IL-1β, IL-2, IL-23p19, TNF-α and CCL28 expression was assessed in the colonic mucosa of 26 dogs with IBD and 9 healthy controls and in the colonic cytobrush samples of 25 dogs with IBD and 9 healthy controls, while IL-12p40 expression was assessed in the colonic mucosa of 16 dogs with IBD and 9 healthy controls and in the colonic cytobrush samples of 15 dogs with IBD and 7 healthy controls due to the limited availability of samples. Here, IL23A is linked to inflammatory bowel disease.